Superflash
by Calvin Night
Summary: The DEO encounters The Flash, who warns them of incoming disaster. Will their combined forces take it, and what is he hiding from them?
1. Chapter 1

**A/N: Deviates from canon since the recent Flash episode implied that Supergirl is on another Earth in the multiverse. Also, I've determined National City to be the equivalent to Chicago, since Metropolis is basically New York and a hop-skip away. Central City is, in canon, in Missouri.**

 **Things will make more sense with Barry's POV, and I'll alternate between the Supergirl and Flash world/POV per chapter.**

"Good work, Supergirl," stated Hank Henshaw. The head of the DEO looked impressed, surprisingly, before turning his gaze back on the two new prisoners. Both were blond, a twin brother and sister pair. They looked irritated, but otherwise were rather silent. "These two have been terrorizing their way up north until they met you."

"Yeah, they weren't exactly a piece of cake," Kara grimaced, still slightly sore from the recent battle as she turned to him. "Are you sure they are human?"

"Not considering their super-strength?" Henshaw retorted rhetorically. "No doubt about it."

"Facial recognition got a hit from a database in Central City." Alex reported as she joined the two, reading off her PDA. "They're labeled as the 'Terror Twins', Tuppence and Tommy. Noted for super-strength, near-invulnerability-"

"Tell us something we don't know," Henshaw interrupted. Alex scrolled through the database's files.

"There's a note about the particle accelerator explosion but it's unclear if there's correlation given that their whereabouts weren't confirmed at the time of the incident." Alex paused as she looked over the data with more intensity. "This is from-" The Martian-in-disguise held up a hand and looked around. Kara tensed as a blur of red entered her vision. A masked man stopped, clad in red, panting, while in a defensive position. Alex and the director immediately trained their sidearms on him.

"Who are you?" demanded Henshaw. The man held up a finger, falling to his knees as he weakly kept his hand raised. Kara noticed the lightning emblem across his chest. _The Flash. Strange that he's here, although Miss Grant would kill me if she knew I met him and didn't arrange a-_ The Kryptonian shook her head. It was strange to think of her employer at that moment; she needed to concentrate. Hank lowered his weapon after a few seconds, prompting Alex to, hesitantly, do the same. The Flash started to regain his composure.

"There's a lot we need to do, together this time, Kar- I mean, Supergirl," Kara caught his verbal slip, and knew that her allies did too with a knowing glance between the three of them. The Flash knew who she was. Henshaw studied him a moment longer then nodded to the group.

"Why should we trust you?" Alex asked. Henshaw blinked. The Flash pointed in the directions of the twins.

"S.T.A.R. Labs would like to kindly request that the vague, probably morally dubious, government agency keep their noses out of our research. " The Flash stated, avoiding the initial question. "Well, actually it was more to check you guys out and that's where things would've gone wrong-." He stopped himself as he sighed, standing up. "As for trust," he said, his eyes resting on Alex. "I'll see you tomorrow." In nearly a blink, he was gone. A piece of paper floated to the ground from where he stood. Kara grabbed it.

 _15:00, Big Belly Burger. Order for seven. 400 miles is a lot of calories._

* * *

Alex Danvers didn't consider herself unpatriotic, but staring at seven untouched burgers at the empty seat across from her didn't live up to the promises the American Dream had to offer. Where was he? After her initial access to the file on the 'Terror Twins' (Alex, although seeing the inspiration behind the name, felt that it was silly to codename characters like in the comics), the DEO had been unable to re-hack the systems at S.T.A.R. Labs to discover any files related to the Flash or other meta-humans; their operating systems fried after establishing contact with a virus protecting the firewall. She snapped from her thoughts as someone stumbled into the restaurant. He seemed rather ordinary- brown hair, smooth jawline, and chocolate, almost puppy-like eyes.

"Oh, hey," Alex narrowed her eyes as he approached the table. The agent knew that the director would be identifying the stranger the minute he outed himself. Information popped up on her PDA: _Bartholomew Henry Allen, Central City CSI. Recently acquired ownership of S.T.A.R. Labs._ "My name's Barry, Barry Allen." He reached out to shake Alex's hand.

"Agent Danvers," she answered, taking it. Alex expected the Flash to be...someone less obviously dorky. However, he did remind her of Kara; both were quirky when they didn't have to play the role of a superhero. Barry took a seat and began to dig into his first burger.

"National City is so-" he paused, taking another bite into his burger. Alex wasn't surprised that he nearly inhaled it- superspeed was his superpower- but his speed was only slightly faster than an average human. _He has control over his powers, especially for acquiring them a year ago._ The agent researched Central City and the various meta-humans prior to the meeting. All reported cases of meta-human activity, besides a potential 15 year old file, occurred after the particle accelerator- notably at S.T.A.R. Labs- incident. The DEO kept tabs on the various happenings, but superpowered humans didn't fall under their jurisdiction, and they had pulled all their resources to focus on the recent Kryptonian threat. "Alex?"

"How do you know my name?" she asked suspiciously. Alex noticed he had finished while she spaced out. The Flash looked like a deer facing headlights for one second, then plastered a grin and ran his hand through his hair nervously.

"I do my own research," Alex stared at him, blank-faced as she knew he wasn't exactly telling the truth. Allen's words seemed accurate, but the agent could sense that there were something he didn't want to spill. Kara wouldn't like it, but she could blackmail him using his secret identity. She didn't plan to execute any threats. "I have a few friends who know their way around a firewall or two. That's why your buddies couldn't get back into S.T.A.R. Labs- although, you guys might've impressed the best computer hacker in the world, which is saying something."

"What are you not telling me?" Alex asked as she narrowed her eyes. "There's a reason we are here. Talk."

"Okay, yeah, right." Allen inhaled as he leaned on the table. "Let S.T.A.R. Labs contain the two who can be on the same javelin team as a Kryptonian without sharing her weakness."

"How is S.T.A.R. Labs more secure?" Alex suspected he changed the topic. She was concerned that he was aware of Kryptonite, but she didn't want to unintentionally give up any information.

"We keep rogue meta-humans contained in the spaces of the particle accelerator- we're used to it. Besides, we've been working on inhibiting those kind of powers," Alex straightened her posture, defensively. That kind of technology could fall into the wrong hands and be inflicted on her sister. "As well as finding a place for them to go- they can't exactly go into Iron Heights and expect to be detained."

"And I'm supposed to trust the owner of an organization that is responsible for all this rogue activity to have custody over them? Wasn't this meeting meant to establish trust?"

"Yes well," Allen sighed. "Sorry, it's been a long week. I figured my presence here- without the mask- might have been enough- the whole secret identity thing." The Flash suddenly grimaced. He brought up a hand to massage his temples. "Ah, sorry, just a massive headache all of a sudden." A few seconds later he was fully recovered. The agent received another notification on her PDA.

 _This is urgent. Meet me on the rooftop of CatCo, bring him, and get Supergirl._


	2. Chapter 2

**A/N: I wanted to update this earlier, but life. Enjoy.**

* * *

That came out of nowhere, Barry noted, after his headache cleared. Normally he wouldn't have bothered to question a bodily function, but Barry felt...unnerved. It felt like someone was pressing their fingers against his forehead; Barry briefly thought that he saw the color green before he, immediately, returned back to normal.

"Look," said Alex, standing up as she typed on her PDA. "To get a start on gaining our trust, come with me."

"Where are we going?" Barry asked, hesitantly as he rose to his feet. This wasn't going according to plan- not that he'd expected the plan to work, given his recent experiences. The agent grabbed him by the forearm as she stormed past him, causing him to stumble but to quickly follow her lead.

"The rooftop of CatCo Media." Alex said as they left the restaurant. Barry used the opportunity to quickly duck into an alleyway, quickly bringing Alex with him. Before she could say a word, he super-changed into his disguise.

"Want a ride?" he smirked, amused how he'd caught the agent off-guard and speechless. A second later, Alex recomposed as she considered his offer.

"If you get us there fast," Barry noticed how her logical thinking outweighed her current distrust of him- it was evident it her calculating brown eyes. "The building's ten blocks northeast from here- shouldn't be hard to find."

"Got it," Barry said, before he picked the agent up and dashed.

As he ran, his mind wandered back to the past, or rather, the future. _I need to protect her,_ he remembered, reliving the moment where tears streamed down Kara's face. Barry's heart tightened as he recalled the others he'd lost that day. _I need to protect them._ Despite his hesitance with altering the timeline, it was the Kryptonian who convinced him; Barry knew that some people were worth the risk. He informed Cisco and those at S.T.A.R. Labs after he made the jump in the middle of his first visit to National City. Of course, they disapproved, but avoided his explanation. Barry knew they trusted his judgement, and advised him to keep his future acquaintances- friends- out of the loop. The Flash didn't want them to behave irrationally- time travel was already complicated.

"Whoops, missed that big time," Barry exclaimed as he passed by the media hub. He doubled back, gaining enough momentum to vertically run up the building. _I'm getting distracted,_ Barry chided to himself, as he made it to the rooftop and skidded to a stop. He set down the agent, noticing the look of surprise on her face. The Flash resisted the urge to tease her- she wasn't the Alex that he knew yet.

"Alex," Barry turned to see Kara, who had emerged from the stairwell onto the roof, wearing her supersuit and cape. Her posture was tense as she observed Barry. "Surprised to see you up here...so quickly."

"I may have hitched a ride." Alex inhaled as she closed her eyes, likely still dazed from the experience. Kara raised an eyebrow at the masked forensic scientist before turning to her sister.

"Where's Hank?"

"Director Henshaw...he wasn't expecting us to get here so quickly. He's on his way," Alex informed them, after checking her PDA. Barry shifted his weight from side to side, trying to soften the mood.

"Nice city," The Flash commented, trying to break the ice. "It's nice to be somewhere else for a change."

"Why are you here?" The blonde asked, tilting her head to the side.

"He's here for those two you took down," Her sister answered, before he could get in a word. "He says that his facilities could contain them."

"We have that under control," Kara stated, although Barry knew she was bluffing. The DEO didn't have a standard procedure for meta-humans; they were more invested in Kryptonians and other forms of alien life. Barry knew they would contact A.R.G.U.S at some point- he needed to make sure that didn't happen. He'd already contacted Diggles, but since they never figured out who the mole was, Barry was unable to provide sufficient intel. His best course of action was to start from the beginning.

"The DEO isn't authorized to contain meta-humans," Barry mentally bit his tongue, stopping himself from revealing more of his knowledge. He'd already made the mistake of referring to Alex and Kara by their names. "According to A.R.G.U.S."

"You have contacts there?" questioned Alex. Barry nodded in response. The agent seemed satisfied, while Supergirl pivoted her attention towards her.

"Does that mean that Livewire isn't with the DEO?"

"We weren't authorized to hold her. The General wanted to contain her; Hank found an alternate." Supergirl tilted her head

"Who are you?" she asked, changing tactics. Barry extended his hand after he briefly took off his mask.

"Barry Allen," he introduced as he shook her hand, pulling his mask back on in the process. The Flash was on top a media hub- while it was worth it to establish trust, it was unwise to bare his identity. Barry was lucky no one seemed to notice him; he chalked it up to the citizens being unfamiliar with his presence and streaking speed. Kara seemed to have a recollection as her stare intensified.

"How did you know my name?" The Kryptonian asked. Barry could also see the suspicion present in Alex's eyes. Before he could respond, a new voice interjected.

"He's from the future," Hank Henshaw declared.

* * *

Tommy and Tuppence...Tommy and Tuppence… thought Cisco as he browsed through their files. He, despite his best intentions, wanted to know why Barry would risk travelling through time- again- to snatch up a pair of metahumans before someone at A.R.G.U.S. got their paws on them. It puzzled him to no end; however, he had other ways of going about it.

"Come on, Cisco," he chided to himself, as he sat comfortably in a chair. He inhaled. Get ready to feel the vibrations of the universe. As he concentrated, his mind quickly flashed back to the Dr. Evil Harrison Wells, to which he shuddered. "Okay, maybe, feel the force, Luke?" Cisco thought aloud. He took a deep breath, and then another, before closing his eyes and tentatively putting on his visor.

This never gets any less cool, Cisco marveled as a familiar blue tunnel appeared before him. The scientist had a vague understanding of how this power worked; he theorized that his subconscious, steered by his conscious, translated the traces of vibrations he was able to sense (explaining his ability to concentrate) into imagery.

As his senses detailed the surroundings, Cisco could see the two siblings, donned in prison garb, following someone in front of them. The Vibe took note of the sibling's new attire, particularly to their red and green crystal necklaces. He couldn't make out the other person, but Cisco could tell that they swiped an identification card before letting the two out of the prison premises.

The scene changed, showing Barry running in an unfamiliar city. Cisco could tell that the Flash was drawing an enemy out, as he bolted past city limits. Cisco jolted as a beam of light crossed his vision, leaving scorching trails upon the asphalt. A figure flew past him, but before Cisco could see anything else, he felt a hand upon his shoulder.

"Gah!" he exclaimed as he jumped away from his chair, pulling off his visors. The scientist didn't need to turn around to know who'd interrupted his vision. After experiencing the same hand cut open his heart, Cisco could recognize its owner anywhere. "Harry!"


End file.
